2021-11-09 PMIC RK817 处理POWER键流程linux 部分的简单分析，dts 中会用 interrupt-parent interrupts去处理按键的中断。

海月汐辰

5247人浏览 · 2021-11-09 14:27:33

海月汐辰 · 2021-11-09 14:27:33 发布

一、硬件电路分析

先来看pmuc rk817 power按键的电路原理图，power 按键是连接到pmic，pmic 检测到按键事件后在通过PMIC_INT_L （GPIO0-A3）发信号给cpu。

二、软件上的实现

1、从上面的原理图知道PMIC_INT_L 是连接到GPIO0-A3，cpu需要处理这个gpio的中断事件，首先得配置dts。interrupt-parent = <&gpio0>; interrupts = <3 IRQ_TYPE_LEVEL_LOW>;定义中断pin。

2、检测到是这个pmic的id就调用对应的的cells，这个方法之前的都没有用过，用这种方法可以调用不同的驱动。

3、注意这个name是"rk805-pwrkey"，会通过这个name去打开一个平台设备文件处理按键事件。

4、这个地方定义检测中断pin的上升和下降沿。

5、处理按键事件的驱动文件\kernel\drivers\input\misc\rk805-pwrkey.c 注意name = "rk805-pwrkey"和上面的是对应的。

/*
 * Rockchip RK805 PMIC Power Key driver
 *
 * Copyright (c) 2017, Fuzhou Rockchip Electronics Co., Ltd
 *
 * Author: Joseph Chen <chenjh@rock-chips.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under  the terms of the GNU General  Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

static irqreturn_t pwrkey_fall_irq(int irq, void *_pwr)
{
	struct input_dev *pwr = _pwr;

	input_report_key(pwr, KEY_POWER, 1);
	input_sync(pwr);
        printk("pwrkey_fall_irq \n");
	return IRQ_HANDLED;
}

static irqreturn_t pwrkey_rise_irq(int irq, void *_pwr)
{
	struct input_dev *pwr = _pwr;
        printk("pwrkey_rise_irq \n");
	input_report_key(pwr, KEY_POWER, 0);
	input_sync(pwr);

	return IRQ_HANDLED;
}

static int rk805_pwrkey_probe(struct platform_device *pdev)
{
	struct input_dev *pwr;
	int fall_irq, rise_irq;
	int err;

	pwr = devm_input_allocate_device(&pdev->dev);
	if (!pwr) {
		dev_err(&pdev->dev, "Can't allocate power button\n");
		return -ENOMEM;
	}

	pwr->name = "rk805 pwrkey";
	pwr->phys = "rk805_pwrkey/input0";
	pwr->id.bustype = BUS_HOST;
	input_set_capability(pwr, EV_KEY, KEY_POWER);

	fall_irq = platform_get_irq(pdev, 0);
	if (fall_irq < 0) {
		dev_err(&pdev->dev, "Can't get fall irq: %d\n", fall_irq);
		return fall_irq;
	}

	rise_irq = platform_get_irq(pdev, 1);
	if (rise_irq < 0) {
		dev_err(&pdev->dev, "Can't get rise irq: %d\n", rise_irq);
		return rise_irq;
	}

	err = devm_request_any_context_irq(&pwr->dev, fall_irq,
					   pwrkey_fall_irq,
					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
					   "rk805_pwrkey_fall", pwr);
	if (err < 0) {
		dev_err(&pdev->dev, "Can't register fall irq: %d\n", err);
		return err;
	}

	err = devm_request_any_context_irq(&pwr->dev, rise_irq,
					   pwrkey_rise_irq,
					   IRQF_TRIGGER_RISING | IRQF_ONESHOT,
					   "rk805_pwrkey_rise", pwr);
	if (err < 0) {
		dev_err(&pdev->dev, "Can't register rise irq: %d\n", err);
		return err;
	}

	err = input_register_device(pwr);
	if (err) {
		dev_err(&pdev->dev, "Can't register power button: %d\n", err);
		return err;
	}

	platform_set_drvdata(pdev, pwr);
	device_init_wakeup(&pdev->dev, true);

	return 0;
}

static struct platform_driver rk805_pwrkey_driver = {
	.probe	= rk805_pwrkey_probe,
	.driver	= {
		.name = "rk805-pwrkey",
	},
};
module_platform_driver(rk805_pwrkey_driver);

MODULE_AUTHOR("Joseph Chen <chenjh@rock-chips.com>");
MODULE_DESCRIPTION("RK805 PMIC Power Key driver");
MODULE_LICENSE("GPL");

6、中断处理函数。